Swath rollers are commonly provided to be towed behind a swather tractor to apply pressure onto the swath as after it is discharged from the rear of the tractor.
An example is shown in Canadian Patent No: 599,761 issued Jun. 14, 1960 by Hellegards which shows a simple cylindrical roller attached behind a towed swather.
Many manufacturers have provided towed swath rollers which comprise a wheeled frame with a forwardly extending hitch pole which attaches to the rear of the swather tractor. One example is shown in a brochure by the present Applicants where a transverse beam carried on the ground wheels has a pair of rearwardly extending arms between which is mounted a metal roller drum. The drum has a cylindrical center section with flared frusto-conical ends. The height of the drum can be adjusted on the frame to adjust the pressure on the swath, depending on the thickness of the swath. The ends of the drum can be closed by circular end plates.
This type of swath roller has achieved considerable success and many have been sold by various manufacturers.
More recently the metal drum has been replaced by a plastic rotationally molded drum. The has advantage that it does not rust and can be manufactured cheaply but it has disadvantages that it slips on the crop and therefore may not properly rotate in a rolling action. Also the drum is very light so that it may not apply the required pressure.
One example of a roller of this type is shown in Canadian Patent Application Serial No: 2,299,185 (Worms) of Koenders published Aug. 23, 2001. This provides longitudinally extending ribs on the drum to aid in causing the drum to properly rotate.
Another example is shown in Canadian Patent No: 2,311,692 (Cresswell) of Bourgault issued Mar. 11, 2003. This shows in FIG. 1 a similar arrangement of towed frame in which the width of the drum can be adjusted. In FIG. 2 is shown a different arrangement in which the roller is carried on a pair of arms extending rearwardly from the rear of the tractor. There are no ground wheels and the height of the drum is adjusted by a winch arrangement which lifts and lowers the drum frame at the rear of the arms. This arrangement manufactured by Free Form Plastics has the disadvantage that the amount of pressure on the swath is dependent only on the weight of the drum and this may be insufficient as the drum is a plastic molded drum.
In view of the disadvantages of this system, Free Form Plastics has developed recently a system in which the winch suspension system is replaced by a pair of double acting cylinders which allow the cylinders to press downwardly on the roller.
Swather tractors have in recent years become much larger and more complex with some having independent suspension of the rear wheels. Such tractors are of the type with front wheels which are independently driven to provide a steering action together with castor rear wheels which follow the direction determined by the differential speeds of the front wheels. The towed swath rollers have become inadequate to provide a suitable convenient arrangement for the operator. At the same time there has been an increased demand for swath rolling.